I would say that having a dough docker makes the most sense for cracker-style crusts, especially if a lot of them are to be made. In that case, I would definitely consider buying a dough docker, for the speed of its use. A fork can be used instead of a dough docker so long as care is taken not to completely penetrate the skin. A dough docker has blunt tips that effectively "staple" together the top and bottom surfaces of a skin without completely piercing the skin. One or two passes of a dough docker across the surface of the skin is sufficient. Using a fork will take a lot longer.

A dough docker does not prevent bubbling. Rather, it reduces the likelihood of bubbling. A lot of professional pizza operators use dough dockers either because the dough is underfermented and "bucky" (overly elastic), of low hydration, or because they want to save time by using the dough while it is cold. Some places, like Papa John's, requires all of its workers to use dough dockers for all of their dough skins that are prepared in their stores, whether the dough is cold or not.

If a NY style dough is properly prepared and properly fermented, I see no reason for using a dough docker, or a fork as a substitute for a dough docker. Some operators who use high-gluten flours to make their NY style doughs will use dough dockers but usually it is because the dough is not given sufficient fermentation time, resulting in a bucky dough.